The present invention relates essentially to water-insoluble solid particles coated with at least one layer of at least one product resulting from the reaction between a molecule capable of becoming hydrated in contact with water and at least one lipophilic molecule, and to their use for the manufacture of cosmetic compositions, pharmaceutical compositions or agricultural compositions. These water-insoluble solid particles are preferably used to manufacture anhydrous cosmetic compositions, making it possible to incorporate hydrating molecules into formulations which are generally dehydrating.
The surface treatment of pigments is a technique widely used in the industrial sector. This surface treatment can make it possible for example to improve drying and coverage in the paints sector. Surface treatments of pigments are also technologies used in the cosmetics sector, for example for improving the ability of pigments to be incorporated into cosmetic formulations, or for increasing the adhesion of the pigments to the skin.
Thus, for example, pigments coated with different types of silicones are proposed commercially as cosmetic pigments for make-up applications, the aim being to facilitate the incorporation of the pigments into generally hydrophobic formulations for which the untreated (conventional) pigments generally have little affinity. Thus titanium dioxides coated with silicone polymers and zinc oxides coated with silicone polymers are currently very widely used in cosmetics, particularly in sun protection preparations, which generally contain large amounts of these pigments (it generally being complicated to incorporate said pigments into cosmetic formulations at very high concentrations).
Likewise, some pigments coated with fluorocarbon polymers are also proposed commercially as cosmetic pigments for make-up applications, the aim being to improve their adhesive power while at the same time enabling the formulations to form a film on application (for example the film left by a lipstick or make-up foundation).
It is also possible to find pigments coated with natural polymers such as proteins in general and collagen in particular. The coating of insoluble particles with collagen films has been described in particular in patent U.S. Pat. No. 4,711,783 to Huc et al. These coatings are generally rather unfavorable for the adhesion of the pigments to the skin, and they give rise to manufacturing problems when they are incorporated into make-up formulations. In fact, their hydrophilic nature renders the pigments more hydrophilic on the surface, making the treated pigments more difficult to disperse in the hydrophobic phases which are present in most if not all formulations of make-up preparations.
However, this type of coating is valuable because it enables molecules or macromolecules such as proteins to be introduced into formulations which are generally anhydrous or have a low water content, said molecules or macromolecules themselves being capable of trapping very substantial amounts of water and hence of moisturizing the skin very considerably after application of the products containing them.
This ability to introduce molecules of very high moisturizing power into formulations, particularly anhydrous formulations, is becoming crucial. In fact, the use of volatile molecules, particularly volatile silicones, at a very high concentration in anhydrous formulations, which make it possible to avoid transfer of the pigments onto white surfaces (property of xe2x80x9cno transferxe2x80x9d), also gives rise to very dry formulations which are rather uncomfortable and rather unpleasant when applied. Any substance which makes it possible to counteract these unpleasant sensations on application and to improve the cosmetic feel, particularly in so-called xe2x80x9cno transferxe2x80x9d formulations, is of very great interest to those skilled in the art.
One main object of the invention is to solve the new technical problem consisting in the provision of a novel formulation of water-insoluble solid particles having a good dispersibility in hydrophilic media, hydrophilic molecules or molecules with a very high moisturizing power, enabling the formulation to be used in the cosmetic or pharmaceutical sector or in agriculture.
Another main object of the present invention is to solve the new technical problem consisting in the provision of novel formulations of water-insoluble solid particles combined with hydrophilic molecules, while at the same time preserving an adhesion capacity and avoiding the problem of transfer, especially where pigments are involved.
Another main object of the present invention is to solve the new technical problem consisting in the provision of novel solid particles such as pigments, improving the compatibility with mostly hydrophobic phases.
The invention makes it possible for the first time to solve all these technical problems in a simple and relatively inexpensive manner which can be used on the industrial scale, especially in cosmetics or pharmaceutics or in agriculture.
Thus the invention proposes to solve the above technical problems, namely to introduce hydrophilic molecules, or even hydrophilic polymers, into the lipophilic phases of emulsions or into anhydrous formulations, while at the same time preserving a good dispersibility of the pigments, with the aim of providing softness and homogeneous spreading on application.
In fact, to improve the contact between the hydrophilic polymers used to coat the pigments, on the one hand, and the formulation consisting of mostly hydrophobic phases (silicones or synthetic or vegetable oils), on the other hand, the inventors attempted to graft fatty chains onto these natural polymers. The lipophilic polymers were formed either before being used to coat the pigments, or directly in the presence of the pigment to be treated, so as to enhance the interactions between the three compounds. The galenical properties of formulations containing one or other of these two complexes formed in this way were compared with the galenical properties of formulations containing each of the compounds separately, and unexpected properties were obtained in these studies, which are presented below.
According to a first feature, the present invention provides water-insoluble solid particles which are coated with at least one product resulting from the reaction between at least one of said molecules capable of becoming hydrated in contact with water and at least one lipophilic molecule.
In one advantageous embodiment, the lipophilic molecule is a hydrocarbon organic molecule having from 4 to 30 carbon atoms which is reacted in a reactive form with the molecule capable of becoming hydrated in contact with water.
In another advantageous embodiment, the water-insoluble solid molecules are selected from an organic or mineral pigment, a mineral filler such as talcum, a physical sun filter such as a metal oxide, particularly a zinc oxide or a titanium dioxide, and a chemical sun filter.
In yet another advantageous embodiment, the molecule capable of becoming hydrated in contact with water is selected from an amino acid, a peptide, particularly with a molecular weight of less than 5000 Daltons, a protein, a polysaccharide, an oligosaccharide, a gum, a vinylic polymer and a fluorinated polymer.
In yet another advantageous embodiment, the above-mentioned protein has an average molecular weight equal to or greater than 5000 Daltons and less than 1,000,000 Daltons, preferably less than 300,000 Daltons, and is selected in particular from collagen, gelatin, albumin, ovalbumin, elastin, reticulin, fibronectin, keratin, silk, laminin, desmosin and isodesmosin, proteoglycans of the extracellular matrix, glycosaminoglycans such as hyaluronic acid, caseins, lactalbumin, lactoglobulins, enzymes extracted from animal tissues, a protein derived from plants, such as wheat protein, unicellular or multicellular alga protein, maize protein, pea protein, lupin protein, bean protein, horse bean protein, cotton protein, almond protein, soya protein, sunflower protein, alfalfa protein and oat protein; cellulose and derivatives thereof such as alkyl or hydroxyalkyl cellulose, notably ethyl cellulose, hydroxyethyl cellulose, propylcellulose, and hydroxypropylcellulose; chitosan and derivatives thereof such as alkyl or hydroxyalkyl chitosan, notably hydroxypropyl chitosan, starch, maltodextrin, polyvinyl alcohol and a polyvinylpyrrolidone, and mixtures thereof.
In yet another advantageous embodiment, the above-mentioned lipophilic molecule is an organic molecule having from 4 to 30 carbon atoms, particularly a hydrophobic, saturated or unsaturated, linear, branched or cyclic C4-C30 lipophilic fatty molecule which can be converted to a reactive form such as a C4-C30 fatty alkyl halide, C4-C30 fatty acid halide or C4-C30 fatty acid anhydride.
In yet another advantageous embodiment, the above-mentioned lipophilic molecule is selected from a C4-C30 fatty acid, particularly butyric acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, ricinoleic acid, oleic acid, linoleic acid, linolenic acid or undecylenic acid, and the corresponding C4-C30 fatty alcohols and fatty amines, derivatives, notably esters, of said fatty acids, of said fatty alcohols and of said fatty amines, and mixtures thereof, preferably lauric, stearic or palmitic acid and especially a mixture of stearic and palmitic acids, laurylamine or hexadecylamine, or decyl alcohol.
In yet another advantageous embodiment, the molecules capable of becoming hydrated in contact with water are first introduced into an aqueous medium, in which they are dissolved or dispersed, after which they are reacted with said lipophilic molecules in reactive form until said reaction product is formed, and then said water-insoluble solid particles are added to the medium containing the reaction product and are dispersed by any means of dispersion, especially by mechanical dispersion.
In yet another advantageous embodiment, the molecules capable of becoming hydrated in contact with water are introduced into an aqueous medium until they have dissolved or dispersed, then said water-insoluble solid particles are dispersed in said aqueous medium, and finally said lipophilic molecules in reactive form are introduced into the aqueous medium to give said reaction product, said water-insoluble solid particles thereby being coated with said reaction product.
In yet another advantageous embodiment, the aqueous medium containing said water-insoluble solid particles coated with said reaction product is adjusted to a pH compatible with a given industrial use, particularly a cosmetic use or a pharmaceutical use or else an agricultural use.
In yet another advantageous embodiment, the aqueous medium containing said water-insoluble solid particles coated with said reaction product is dried by any drying means, particularly by atomization, lyophilization or dehydration under vacuum and preferably by lyophilization.
In yet another advantageous embodiment, the dried product is ground until the particle size is less than or equal to about 200 xcexcm.
In yet another advantageous embodiment, the pigment is coated with at least one layer of at least one product resulting from the reaction between at least one molecule capable of becoming hydrated in contact with water and at least one lipophilic molecule.
In yet another advantageous embodiment, said solid particles comprise a white or colored organic pigment, or a white or colored mineral pigment such as titanium dioxide, zinc oxide, chromium oxide or black, yellow or blue iron oxide, or a mineral filler used particularly for make-up, such as talcum, kaolin, mica, boron nitride, nylon beads, silica, silica beads, said pigment or filler being coated with at least one layer of the product resulting from the reaction of a gum lac with a halide of butyric, capric, caprylic, decanoic, lauric, stearic, myristic, palmitic, oleic, linoleic, linolenic, undecylenic or undecanoic acid.
In yet another advantageous embodiment, said solid particles comprise a white or colored organic pigment, or a white or colored mineral pigment such as titanium dioxide, zinc oxide, chromium oxide or black, yellow or blue iron oxide, or a mineral filler used particularly for make-up, such as talcum, kaolin, mica, boron nitride, nylon beads, silica, silica beads, said pigment or filler being coated with at least one layer of the product resulting from the reaction of hyaluronic acid with a halide of butyric, capric, caprylic, decanoic, lauric, stearic, myristic, palmitic, oleic, linoleic, linolenic, undecylenic or undecanoic acid.
In yet another advantageous embodiment, said solid particles comprise a white or colored organic pigment, or a white or colored mineral pigment such as titanium dioxide, zinc oxide, chromium oxide or black, yellow or blue iron oxide, or a mineral filler used particularly for make-up, such as talcum, kaolin, mica, boron nitride, nylon beads, silica or silica beads, said pigment or filler being coated with at least one layer of the product resulting from the reaction of an acacia gum with a halide of butyric, capric, caprylic, decanoic, lauric, stearic, myristic, palmitic, oleic, linoleic, linolenic, undecylenic or undecanoic acid.
In yet another advantageous embodiment, said solid particles comprise a white or colored organic pigment, or a white or colored mineral pigment such as titanium dioxide, zinc oxide, chromium oxide or black, yellow or blue iron oxide, or a mineral filler used particularly for make-up, such as talcum, kaolin, mica, boron nitride, nylon beads, silica or silica beads, said pigment or filler being coated with at least one layer of the product resulting from the reaction of polyvinyl alcohol with a halide of butyric, capric, caprylic, decanoic, lauric, stearic, myristic, palmitic, oleic, linoleic, linolenic, undecylenic or undecanoic acid.
In yet another advantageous embodiment, said solid particles comprise a white or colored organic pigment, or a white or colored mineral pigment such as titanium dioxide, zinc oxide, chromium oxide or black, yellow or blue iron oxide, or a mineral filler used particularly for make-up, such as talcum, kaolin, mica, boron nitride, nylon beads, silica or silica beads, said pigment or filler being coated with at least one layer of the product resulting from the reaction of a polyvinylpyrrolidone with a halide of butyric, capric, caprylic, decanoic, lauric, stearic, myristic, palmitic, oleic, linoleic, linolenic, undecylenic or undecanoic acid.
In yet another advantageous embodiment, said solid particles comprise a white or colored organic pigment, or a white or colored mineral pigment such as titanium dioxide, zinc oxide, chromium oxide or black, yellow or blue iron oxide, or a mineral filler used particularly for make-up, such as talcum, kaolin, mica, boron nitride, nylon beads, silica or silica beads, said pigment or filler being coated with at least one layer of the product resulting from the reaction of an agar with a halide of butyric, capric, caprylic, decanoic, lauric, stearic, myristic, palmitic, oleic, linoleic, linolenic, undecylenic or undecanoic acid.
In yet another advantageous embodiment, said solid particles comprise a white or colored organic pigment, or a white or colored mineral pigment such as titanium dioxide, zinc oxide, chromium oxide or black, yellow or blue iron oxide; or a mineral filler used particularly for make-up, such as talcum, kaolin, mica, boron nitride, nylon beads, silica or silica beads, said pigment or filler being coated with at least one layer of the product resulting from the reaction of a gel of aloe vera with a halide of butyric, capric, caprylic, decanoic, lauric, stearic, myristic, palmitic, oleic, linoleic, linolenic, undecylenic or undecanoic acid.
In yet another advantageous embodiment, said solid particles comprise a white or colored organic pigment, or a white or colored mineral pigment such as titanium dioxide, zinc oxide, chromium oxide or black, yellow or blue iron oxide, or a mineral filler used particularly for make-up, such as talcum, kaolin, mica, boron nitride, nylon beads, silica or silica beads, said pigment or filler being coated with at least one layer of the product resulting from the reaction of a starch or maltodextrin with a halide of butyric, capric, caprylic, decanoic, lauric, stearic, myristic, palmitic, oleic, linoleic, linolenic, undecylenic or undecanoic acid.
According to a second feature, the present invention provides the use of the water-insoluble solid particles coated with at least one layer of said product resulting from the reaction between a molecule capable of becoming hydrated in contact with water and a lipophilic molecule, for the manufacture of a cosmetic composition, a pharmaceutical composition, a food composition or an agricultural composition, preferably for the manufacture of a cosmetic composition.
In one advantageous embodiment, the water-insoluble solid particles are used for the manufacture of a cosmetic composition, particularly an anhydrous cosmetic composition such as a lipstick or make-up foundation.
In one advantageous embodiment, the water-insoluble solid particles coated with the above-mentioned reaction product are first dispersed in a mineral oil such as vaseline, an organic oil, particularly a fatty acid ester such as nonanoyl isononanoate or caprylic/capric triglyceride, a vegetable oil, particularly castor oil, or a silicone, particularly a volatile silicone.
According to a third feature, the present invention also covers a cosmetic composition which comprises water-insoluble solid particles coated with at least one layer of at least one product resulting from the reaction between a molecule capable of becoming hydrated in contact with water and at least one lipophilic molecule as defined above or as described below.
According to a fourth feature, the present invention also covers a pharmaceutical composition which comprises water-insoluble solid particles coated with at least one layer of at least one product resulting from the reaction between a molecule capable of becoming hydrated in contact with water and at least one lipophilic molecule as defined above or as described below.
According to a fifth feature, the present invention also covers an agricultural composition which comprises water-insoluble solid particles coated with at least one layer of at least one product resulting from the reaction between a molecule capable of becoming hydrated in contact with water and at least one lipophilic molecule as defined above or as described below.
According to a sixth feature, the present invention also covers a process for the manufacture of the water-insoluble solid particles coated with at least one layer of at least one product resulting from the reaction between at least one molecule capable of becoming hydrated in contact with water and at least one lipophilic molecule as defined above or as described below, said process comprising a step in which said water-insoluble solid particles are coated with a product resulting from the reaction between said molecule capable of becoming hydrated in contact with water and said lipophilic molecule. Within the framework of the process, the reaction product can be formed after the solid particles have been mixed with the molecule capable of becoming hydrated in contact with water in an aqueous medium, or said reaction product has been formed prior to admixing said solid particles.
The reaction conditions are well known to those skilled in the art and are e.g. those described in prior art document FR-A-2 739 860 to the Applicant, or they are clearly apparent to those skilled in the art from the Examples of manufacture below.